there are 2 same rods, one is conductor and the other is semi-conductor.now they are connected in parallel and a galvanometer is attached with each to measure current in rods.now when a 10 V battery is connected to the systemboth galvanometer shows the same deflection. now the battery is replaced by a 20V battery. then which galvanometer shows greater deflection? and why?

Dear Suchintan,

The semiconductor rod shows more deflection because in semiconductors the current flow is due to the both electrons and holes. So, as we have increased the voltage more electrons and holes are created due to increase of the elctrical potential energy and thus making more electrons go to the conduction band from the valence band. Also due to the heat generated during conduction the electron and hole numberfurther increases. Thus ultimately allowing more current to flow when compared to the conventional conductors whose resistance increases as the temperature increases.

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